(1) Field of the Invention
The present invention relates to a data storage management method for backup memory to be used for, for example, copiers, facsimile machines and multi-functional machines using electrophotography, and in particular relates to a data management method for improving the reliability of the machine-status data stored in the backup memory in the above various image forming apparatus.
(2) Description of the Prior Art
Conventionally, in the backup memory that stores machine-status data in an image forming apparatus, data rewrite etc., are performed based on the data which has been once input. Examples of important machine-status data concerning an image forming apparatus include the total copy/print number, the number of times the photosensitive member has been used. With the increasing development of networking environments, it becomes necessary to know and check the machine-status data for individual users, that is, the usage state including the total print number of an individual user, in order to enhance the accounting system. With this tendency, it becomes more necessary to improve the reliability of the backup data held in the backup memory.
As a storage management method for a backup memory needing rewriting, Japanese Patent Application Laid-Open Hei 7 No. 323617 discloses a method in which a controller analyzes the print data having been input, determines whether a rearranging process needs to be done for the memory, compares the data in a permanent memory controller with the data in the memory when it has been determined that the rearrangement should be done, and reenters that data into a permanent memory. For such backup memory, flash EEPROMs have recently come to be used more frequently.
However, the technique disclosed in Japanese Patent Application Laid-Open Hei 7 No. 323617 not only needs complicated control for data rewriting but also there is doubt about the reliability of the loaded data.
In order to solve the above problem, it is an object of the present invention to provide a data management method for backup memory wherein if an anomaly data value is found in the processing, the data value is made invalid or subjected to a predetermined process to thereby improve the reliability of the backup memory.
In order to achieve the above object, the present invention is configured as follows:
In accordance with the first feature of the present invention, a data management method for backup memory storing machine-status data for use in an image forming apparatus comprising the steps of: determining a first interrelation between a first machine-status data stored most lately in a first storage area and machine-status data stored in storage area other than the first storage area when the machine-status data in a predetermined plural number of storage areas in the memory is renewed in a sequential order; determining a renewal machine-status data based on the first machine-status data if the first interrelation satisfies a predetermined condition; and storing the renewal machine-status data in the storage area to be renewed.
In accordance with the second feature of the present invention, the data management method for backup memory having the above first feature is characterized in that the backup memory employs flash ROMs or EEPROMs.
In accordance with the third feature of the present invention, the data management method for backup memory having the above first feature is characterized in that the machine-status data is renewed when each portion associated with machine-status data provided in the image forming apparatus starts or ends its operation.
In accordance with the fourth feature of the present invention, the data management method for backup memory having the above first feature is characterized in that the backup memory has two types, master and slave memories so as to perform dual storage of the same machine-status data.
In accordance with the fifth feature of the present invention, the data management method for backup memory having the above first feature, further includes the steps of: determining that an anomaly is occurring in the first storage area when the first interrelation does not satisfy the predetermined condition; further determining the first interrelation of between a second machine-status data stored in second storage area before the first machine-status data is stored in the first storage area and machine-status data stored in storage area other than the first and second storage areas; determining a renewal machine-status data based on the second machine-status data if the first interrelation satisfies a predetermined condition; and storing the renewal machine-status data in the storage area to be renewed.
In accordance with the sixth feature of the present invention, the data management method for backup memory having the above fourth feature, further includes the steps of: loading a corresponding first interrelation from a counterpart storage area on the slave backup memory side when the first interrelation related to the storage area on the master backup memory side does not satisfy the predetermined condition; determining a renewal machine-status data based on a renewal relation information relating to renewal of machine-status data and storing the renewal machine-status data into storage area to be renewed on the master side if the first interrelation on the slave side also does not satisfy the predetermined condition; and swapping the master side and the slave side in the backup memory when the first interrelation on the slave side satisfies the predetermined condition.
In accordance with the seventh feature of the present invention, the data management method for backup memory having the above fifth feature, further includes the step of: correcting the first machine-status data based on the second machine-status data when it is found that the first interrelation does not satisfy the predetermined condition.
In accordance with the eighth feature of the present invention, the data management method for backup memory having the above fifth or sixth feature is characterized in that even when it is found that the first interrelation does not satisfy the predetermined condition, the first machine-status data that does not satisfy the first interrelation will not be corrected as long as the first machine-status data does not need to be corrected.
In accordance with the ninth feature of the present invention, the data management method for backup memory having the above fifth or sixth feature, further includes the step of: switching the predetermined plural number of storage area to another predetermined plural number of storage area when the first interrelation does not satisfy the predetermined condition.
In accordance with the tenth feature of the present invention, the data management method for backup memory having the above ninth feature further includes the steps of: when swapping of the storage areas has been repeated, a predetermined number of times during a predetermined period of time, or when swapping of the storage areas has been repeated to a predetermined number of times, informing the user of the current situation through a display member; saving the machine-status data in the backup memory, into a separate, recovery backup memory; initializing the backup memory; and recovering the backup memory using the machine-status data stored in the recovery backup memory.
In accordance with the eleventh feature of the present invention, the data management method for backup memory having the above tenth feature, further includes the steps of: when the initialization of the backup memory and the following recovery operation of the backup memory using the recovery backup memory have been repeated, a predetermined number of times during a predetermined period of time, or when the initialization of the backup memory and the following recovery operation has been repeated to a predetermined number of times, stopping the operation of the machine; and informing the user of the current situation through the display member.